The invention relates to a vehicular interior part such as an instrumental panel and a door trim, and to a method of fabricating the same.
More particularly, the invention relates to a high-class look vehicular interior part having realistic sewing lines formed on the surface of a skin material of a synthetic resin member, and to a method of fabricating the same.
A vehicle includes vehicular interior parts such as an instrumental panel installed in a vehicle interior, and a door trim. The interior parts are made from soft materials to achieve protection of passengers. At the same time, the interior parts contribute to improvement in the sense of beauty in the interior. Particularly, a high-class look product requires creating a sense of handmade. Thus, there has been proposed a vehicular interior material according to the following manufacturing steps (for example, see Japanese Patent Laid-Open Application Publication After Examination No. Hei 7 (1995)-004819). A skin material is stitched with an actual thread when the material is at the stage of a single item. Thus, sewing lines are formed on the surface of the skin material. Next, a pad is attached to the rear surface of the skin material, and the skin material is integrated with a core member. Thus, the interior material is completed.
The related technology described above, however, might involve occurrence of fold wrinkles caused by forming the covering skin into a three-dimensional shape. Once the fold wrinkles occur, it is hard to remove the wrinkles even by heat treatment. During foam molding in subsequent steps, a material of the pad might leak from stitches. The fold wrinkles increase a proportion defective. Thus, the fold wrinkles might cause deterioration of production efficiency and might be one of the causes of manufacturing costs rise. Usually, the pad flexes when the thread is tightened. And then, slightly dented path is formed where the thread of the skin material passes. This path produces high-class look. The sewing lines are formed at the stage of only the skin material. Thus, a product may give an impression of low-class look that the thread is attached to only the surface of the skin material.